The Domain Name Service (DNS) is an important part of the Internet which employs names to identify Internet Protocol (IP) numeric addresses which serve as routing addresses on the Internet. Domain names are generally used as a convenient way to locate information and to reach others on the Internet as all computers communicate by addressing each other using IP addresses. It is the IP numeric address, however, which allows Internet communication, such as a telephone number, and not the domain name associated with the IP address. Thus, in operation the DNS system translates hostnames into numbers. Such DNS translation is oftentimes referred to as a “DNS lookup”. This process occurs when one sends an e-mail or connects to a website, and has been characterized as similar in nature to obtaining the phone number of a person.
Sometimes, however, it is desired to find out what host name is associated with an IP address and to translate an IP address numeric information back into hostname(s). Thus, a numeric address can be translated, or otherwise resolved, by the DNS system to identify corresponding hostnames, which is a process known as reverse DNS resolution, or “reverse DNS lookup”, and which is opposite to the usual name-to-address translation.
The DNS is composed of a directory of all the registered domain names and their corresponding computers registered to particular entities using the Internet, and which is organized in a hierarchical manner. Administration of the DNS starts through a group of Top Level Domain (TLD) servers which hold a list of servers, and which in turn hold data for sub-domains comprising each top level domain. An entity or person will run DNS servers for its own domain and will control DNS data, such as hostname, IP address, and the length of time an address is valid. There are two types of Top Level Domains, and are referred to as generic and countries. Examples of generic domains include .com (commercial), .edu (educational), .gov (United States government or municipality), .net (network providers), .int (international organizations), .mil (United States Armed Forces) and .org (non-profit organizations). Country domain names include one entry for each country, such as, for example, .ca (Canada), .th (Thailand), .am (America), and .bo (Bolivia). In a manner similar to telephone numbers, there may be multiple domain names which resolve to the same IP address. Conversely, a domain name may resolve to multiple IP addresses.
As is also known, Internet Web sites usually maintain a list of the addresses of visitors to a site. Reverse domain name resolution of such addresses, or translation of IP addresses back to domain names, will reveal a host of useful information associated with the IP address, such as, inter alia, geographic origin, authentication, hacker detection and tracing, spam detection and tracing, tracing traffic that goes through Firewalls, documentation and e-mail server validation, and other domain name information which can be used, for example, with who is to find out who administers a block of addresses. An IP address that is used on the Internet should have a proper configuration for a reverse DNS lookup, the result of which should match a forward lookup. In other words, when the name associated with an IP address is looked up one should be able to look up the IP address associated with that name to obtain the IP address initially observed or logged. Questions as to legitimacy of source arise when a domain name cannot be resolved, or a name is resolved which does not match an IP address, and which is perhaps indicative of spamming activity as a spammer oftentimes employs an invalid address which does not match a domain name. As reported, for example, in some spam blocking methods, a reverse DNS lookup program inputs an IP address of incoming messages to a DNS database. If no valid name is found to match the IP address a server blocks the incoming message.
Reverse DNS lookup to locate domain names that are in use and/or registered, and consequently those which are available for use by others as domain names and/or trademarks is extremely important in today's world to insure that a mark intended for use does not infringe anothers' name or mark, and/or is not confusingly similar to a registered name. Such a method will help to avoid unnecessary trademark litigation for infringing the Intellectual property rights of others and the waste of capital resources spent on promoting domain names and marks, or confusingly similar renditions, of names already in use by others. Additionally, such reverse DNS lookup will also ensure that a valuable domain is not accidently deleted or dropped from a registry, and further serve to alert one interested in registering a domain name which was previously unavailable.
Reverse name resolution, however, may oftentimes be problematic. For example, while reverse resolution may no doubt be effective for blocking spam, it is also equally effective in blocking legitimate e-mail if an existing domain name is not found. Various network glitches, such as improperly configured networks or servers, can prevent legitimate messages from getting through a reverse DNS spam filter. One recent notable example is AT & T World Net's attempted use of reverse DNS in conjunction with other anti-spam software which failed in short order and was removed in twenty-four hours after deployment, as many subscribers reported the nondelivery of e-mail messages. See CNET news article, “AT & T spam filter loses valid e-mail” (January, 2003). In addition to hosts having a forward DNS from name to numeric IP address, which may or may not have a reverse DNS from address to name, the sheer numbers of IP Internet addresses, said to be in the billions, with many millions of them having host names entered into the DNS system would seem to make reverse resolution a daunting task. Other problems that have interfered with efficient resolution include requiring responses from multiple systems to resolve DNS queries, adverse network conditions with overloaded sections of the Internet not responding to queries, and, for various reasons, the unavailability of name servers responsible for administering DNS data. Additionally, some Internet Service Providers (ISPs) for whatever reason do not enter their addresses in the DNS system.
In a standard DNS process of turning a hostname into an IP address, the process starts with a company registrar that a person's or an entity's domain name has been registered with. The DNS servers that are responsible for the domain name are identified to the registrar which forwards this information to root servers, or the parent servers, for the person's TLD. Anyone globally may now access the person's domains and the person may send them to any IP address as desired or contemplated. The domain name's owner and registrar has complete control over her domains, and may send people to any IP, notwithstanding whether the domain name owner has control over such IPs.
Conventional reverse DNS methods work in a similar manner. Identifying domain names associated with an IP address typically starts with a user's ISP, or whoever is responsible for designating the user's IP address. The domain name owner lets it be known what DNS servers are responsible for reverse DNS entries or queries for her IPs, and the ISP provides this information when the DNS servers are queried for reverse DNS entries, or reverse DNS entries or queries can be entered on a DNS server. With such public information anyone in the world may look up reverse DNS queries or entries for the person's IPs, and the person can return any hostname as desired, whether or not the person has control over a particular domain. A major problem with this method is that if a person's ISP is not aware of DNS servers to process reverse DNS inquiries for their IPs then such information will not be sent to a root server and no one will be able to access the person's DNS servers for reverse DNS lookups. Additionally, conventional DNS methodology will reveal only one domain name per IP address, whereas there may be many names associated with the IP address.
In one proposed partial solution to domain name location, in U.S. Patent Application Publication No. 2003/0149690 there is disclosed a method and apparatus for searching domain names world wide, and which purports to be effective in searching for all variations of a domain name in all jurisdictions, including those which do not make their zone file data available. This method uses what is referred to as data mining techniques in domain space by compiling databases combined with servers and a network of computers to search for registered domain names world wide. Searches for currently registered domain names are undertaken using certain letter/character strings and for domain names containing more than one letter/character string. Additionally, an end user is notified of newly identified domain names that match a predetermined search criterion such as to provide a domain name watching tool. This method, however, does not solve such problems as outlined above.
In U.S. Patent Application Publication No. 2002/0073231 there is disclosed a tracerouting method for a list of Internet hosts which is said to be effective for performing DNS lookup, and is also said to be effective in blocking/filtering out unwanted messages at the point of message receipt to pass on only expected messages to the rest of a program. Such a method is undesirable as many legitimate messages may be blocked in an attempt to reduce spam. Further, this method relies on Internet tracerouting which involves querying as to the path that messages take when going from one computer to another, or a list of computers that a message is routed through on its way to a final destination. Such data gathered from the routing operation is said to identify the Internet address, i.e. the IP address, and the Name of the computer, i.e. the Domain name. However, no reverse DNS lookup methods are contemplated or described in this method, and which the described method would arguably profit from.
Therefore, as can be appreciated by those persons utilizing the Internet in any way, there exists an important need, and a long overdue solution, for a reliable reverse DNS lookup method and system to identify all, or substantially all, hostnames associated with an IP address. There also exists an important need for such a reliable reverse DNS method and system to perform such important diverse tasks as, inter alia, diagnostics, security functions such as to trace hackers and to prevent spamming and various other authentication functions employing dual lookup, IP-to-name and name-to-IP mapping. There further exists an important need to monitor domain name registration and usage throughout the Internet, and to identify historical and current use of particular domain names for purposes of availability for registration and use and avoidance of intellectual property disputes and infringing upon the property of others.